Comparison of dual-chamber pacing versus septal myectomy for the treatment of patients with hypertropic obstructive cardiomyopathy: a comparison of objective hemodynamic and exercise end points.

OBJECTIVES: The purpose of this study was to compare the treatment effects of septal myectomy with dual-chamber pacing in patients with hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: The optimal treatment for symptomatic patients with drug-refractory HOCM is unknown. Both dual-chamber pacing and surgical myectomy may result in subjective symptom improvement. However, no direct comparisons with objective end points have been reported. METHODS: Thirty-nine patients with symptomatic HOCM were analyzed in this concurrent cohort study. Twenty patients underwent surgical myectomy, and 19 received dual-chamber pacemakers based on patient preference. These patients had prospective baseline and follow-up evaluations including physician assessment, echocardiography and standardized metabolic treadmill exercise testing. RESULTS: Baseline symptom status, left ventricular outflow tract gradients, exercise times and maximal oxygen consumption peak were similar between the two groups. Left ventricular outflow gradient was reduced from 76+/-57 to 9+/-17 mm Hg (p = 0.0001) after myectomy, and from 77+/-61 to 55+/-39 mm Hg (p = 0.07) after pacing (p = 0.02 for comparison with myectomy). Ninety percent of myectomy patients experienced symptomatic improvement as compared with 47% in the pacing group. Exercise duration increased significantly from 6.6+/-2.8 to 8.7+/-3.0 min (p = 0.0003) after myectomy compared with a change from 6.4+/-2.1 to 7.0+/-2.2 min (p = NS) in the pacing group. Maximal oxygen consumption increased from 19.4+/-6.4 to 22.2+/-6.5 ml/kg/min after myectomy (p = 0.004), whereas the pacing group did not experience any significant change (19.6+/-6.5 vs. 20.1+/-6.5 ml/kg/min, p = NS). CONCLUSIONS: Surgical myectomy and dual-chamber pacing improve subjective measures of functional status in patients with symptomatic HOCM. In this nonrandomized study, myectomy offered greater reduction in left ventricular outflow tract gradients and larger improvements in objective measures of patient symptoms and functional status when compared with dual-chamber pacing.     

老年肥厚型梗阻性心肌病消融和起搏器治疗的对照观察

目的比较老年肥厚型梗阻性心肌病患者接受经冠状动脉消融肥厚心肌（TASH）或起搏器治疗的有效性和安全性。方法23例充分药物治疗不满意,心功能Ⅲ级（NYHA）以上的老年肥厚型梗阻性心肌病患者随机接受心肌声学造影指导下的TASH或根据血压优化PR间期的右心双腔起搏器治疗。其中2例接受TASH治疗者并发永久起搏器依赖而安装永久起搏器。对单纯接受TASH（13例）或起搏器（8例）治疗者进行了平均24个月的随访。结果接受两种治疗方法的患者心功能和主观症状积分均得到显著的改善。TASH组心功能由3．2±0．7级改善到1．5±0．5级,综合症状积分由5．9±1．6下降到1．8±0．7,P均〈0．001。起搏器治疗组心功能也由3．0±0．1改善到1．9±0．6级,综合症状积分也由4．5±1．3下降到2．3±1．6,P均〈0．01。综合症状改善程度TASH组明显优于起搏器治疗（4．2±1．5比2．3±1．3,P=0．007）。左心室流出道压力阶差TASH组平均下降了（79．9±35．5）mmHg（1mmHg=0．133kPa,P〈0．001）,起搏器治疗组平均下降了（49．3±37．7）mmHg（P〈0．05）,平均下降率分别为84％和53％。左心室流出道压力阶差下降率〉75％和〈50％TASH组分别有10例和1例,起搏器治疗组分别有4例和3例。TASH组治疗后室间隔厚度、左室舒张末径、收缩末径与术前比较变化显著[分别为（22．2±4．1）mm比（17．1±3．2）mm,（41．5±5．3）mm比（44．7±4．6）mm,（23．5±4．4）mm比（28．3±3．6）mm,P均〈0．05],但没有左室收缩功能异常。随访中,TASH组3例阵发性心房颤动中有2例转为慢性心房颤动,起搏器治疗组中2例阵发性心房颤动中1例发展成慢性心房颤动。结论TASH和起搏器治疗两种方法均能使老年肥厚型梗阻性心肌病患者心功能和综合症状得到显著改善,综合症状改善TASH优于起搏器治疗。TASH显著降低左心室流出道压力阶差,起搏器治疗中等程度降低心室流出道压力阶差。TASH导致的左心室流出道重构不会导致老年肥厚型梗阻性心肌病患者收缩功能的异常和左心室的扩张,但同样存在并发症,甚至严重并发症发生的可能。     

Comparison of dual-chamber pacing with nonsurgical septal reduction effect in patients with hypertrophic obstructive cardiomyopathy

OBJECTIVES: The aim of the study was to compare the influence of dual-chamber pacing vs. nonsurgical septal reduction on hemodynamic and morphological parameters in patients with obstructive form of hypertrophic cardiomyopathy. METHODS: Nineteen patients with dual-chamber pacing (group I) and 9 patients who underwent nonsurgical septal reduction (group II) were studied at baseline and after a 6-month follow-up. The changes of left ventricular outflow tract gradient and posterior wall thickness (as an index of left ventricular hypertrophy regression) were compared. RESULTS: The baseline left ventricular outflow tract gradient was comparable between group I and group II (77+/-25 vs. 82+/-25 mm Hg, p>0.05). At 6-month follow-up, the left ventricular outflow tract gradient was reduced to a similar level in both groups (28+/-19 vs. 25+/-12 mm Hg, p>0.05). At baseline, posterior wall hypertrophy was comparable between groups (12.9+/-1.7 vs. 13.6+/-2.2 mm, p>0.05). During follow-up, the posterior wall thickness was unchanged in the pacing group (12.9+/-1.7 vs. 12.6+/-1.6 mm, p>0.05), whereas nonsurgical septal reduction induced regression of left ventricular hypertrophy in myocardial region remote from the infarcted septal segment (13.6+/-2.2 vs. 10.5+/-2.3 mm, p<0.003). CONCLUSION: Despite comparable reduction of instantaneous left ventricular outflow tract gradient, the nonsurgical septal reduction decreased posterior wall thickness, whereas pacing did not reduce left ventricular hypertrophy. Thus, regression of left ventricular hypertrophy that appeared solely after nonsurgical septal reduction may reflect the more permanent reduction of left ventricular pressure overload. Thus, not only hemodynamic but also morphological benefit from nonsurgical septal reduction seems to indicate the superiority of this method over dual-chamber pacing.     

Comparison of ethanol septal reduction therapy with surgical myectomy for the treatment of hypertrophic obstructive cardiomyopathy.

OBJECTIVES: This study was designed to compare the hemodynamic efficacy of nonsurgical septal reduction therapy (NSRT) by intracoronary ethanol with standard therapy (surgical myectomy) for the treatment of hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Nonsurgical septal reduction therapy has gained interest as a new treatment modality for patients with drug-refractory symptoms of HOCM; however, its benefits in comparison to surgery are unknown. METHODS: Forty-one consecutive NSRT patients at Baylor College of Medicine with one-year follow-up were compared with age- and gradient-matched septal myectomy patients at the Mayo Clinic. All patients had left ventricular outflow obstruction with a resting gradient > or =40 mm Hg and none had concomitant procedures. RESULTS: There were no baseline differences in New York Heart Association class, severity of mitral regurgitation, use of cardiac medications or exercise capacity. One death occurred during NSRT because of dissection of the left anterior descending artery. At one year, all improvements in both groups were similar. After surgical myectomy, more patients were on medications (p < 0.05) and there was a higher incidence of mild aortic regurgitation (p < 0.05). After NSRT, the incidence of pacemaker implantation for complete heart block was higher (22% vs. 2% in surgery; p = 0.02). However, seven of the nine pacemakers in the NSRT group were implanted before a modified ethanol injection technique and the use of contrast echocardiography. CONCLUSIONS: Nonsurgical septal reduction therapy resulted in a significantly higher incidence of complete heart block, but the risk was reduced with contrast echocardiography and slow ethanol injection. Surgical myectomy resulted in a significantly higher incidence of mild aortic regurgitation. Nonsurgical septal reduction therapy, guided by contrast echocardiography, is an effective procedure for treating patients with HOCM. The hemodynamic and functional improvements at one year are similar to those of surgical myectomy.     

Long-term follow-up of patients with obstructive hypertrophic cardiomyopathy treated with dual-chamber pacing

In this study, patients with obstructive hypertrophic cardiomyopathy (HC) were treated with dual-chamber pacemaker therapy. Long-term follow-up analysis showed that dual-chamber pacemaker therapy in selected patients resulted in a significant reduction in symptoms and in the left ventricular outflow tract gradient, which was maintained up to 10 years after implantation. Dual-chamber pacing is of potential long-term benefit in selected groups of patients with obstructive HC.     

Comparison of percutaneous transluminal septal myocardial ablation versus septal myectomy for the treatment of patients with hypertrophic obstructive cardiomyopathy--a meta analysis

BACKGROUND: The effects of percutaneous transluminal septal myocardial ablation (PTSMA) with septal myectomy in patients with hypertrophic obstructive cardiomyopathy (HOCM) are not thoroughly compared. METHODS: Three articles comparing the effects of PTSMA and septal myectomy treatment for HOCM were identified from a search in Pubmed, and a meta analysis was conducted. RESULTS: 177 patients (86 underwent PTSMA and 91 underwent septal myectomy) were included. Interventricular septum thickness was decreased from 22.1 to 15.1 mm (p<0.05) in PTSMA group and from 22.0 to 13.9 mm (p<0.05) in septal myectomy group; left ventricular end-diastolic dimension was increased from 41.8 to 45.2 mm (p<0.05) in PTSMA group and from 41.8 to 43.9 mm (p<0.05) in septal myectomy group; NYHA class was improved from 3.17 to 1.47 (p<0.05) in PTSMA group and from 2.97 to 1.36 (p<0.05) in septal myectomy group; there were no differences in the two groups. However, left ventricular outflow tract gradient was decreased from 76.0 to 15.7 mm Hg (p<0.05) in PTSMA group and from 74.7 to 9.4 mm Hg (p<0.05) in septal myectomy group and the effect of septal myectomy was better than PTSMA (p<0.05). CONCLUSIONS: The effects of septal myectomy treatment for HOCM are better with regard to relief of LVOT gradient, and lower risk of pacemaker requirement, compared to PTSMA. Large randomized clinical trials further comparing the two treatments are suggested.     

Outcome of surgical myectomy after unsuccessful alcohol septal ablation for the treatment of patients with hypertrophic obstructive cardiomyopathy.

OBJECTIVES: We sought to determine the outcome of myectomy after unsuccessful alcohol ablation. BACKGROUND: Alcohol septal ablation results in symptomatic improvement and a reduction in dynamic obstruction in most hypertrophic obstructive cardiomyopathy patients. However, a few patients remain with severe symptoms and obstruction and need surgery. The outcome of these cases is not well known. METHODS: The medical records of 375 patients who underwent alcohol ablation at our institution were reviewed. Twenty patients (5.3%, mean age 53 +/- 18 years, 17 women) subsequently needed surgical myectomy. The New York Heart Association (NYHA) functional class, angina class, exercise duration, left ventricular outflow tract (LVOT) gradient, ejection fraction, and septal thickness were tabulated. The anatomy and distribution of the septal perforator arteries were examined. RESULTS: After ablation, NYHA functional class (3 to 2.5; p < 0.05) and LVOT gradient (93 +/- 23 mm Hg to 71 +/- 26 mm Hg; p < 0.05) were slightly improved, without a change in exercise duration (171 +/- 124 s to 168 +/- 148 s; p > 0.5). Myectomy was performed at 19 +/- 15 months after ablation. There was no operative mortality, but permanent pacing was needed in 2 patients after surgery, and 3 other cases needed pacing before, or as a complication of, alcohol ablation. A significant improvement was noted, with the NYHA functional class decreasing to 1, exercise duration increasing to 423 +/- 171 s, and LVOT gradient decreasing to 6 +/- 11 mm Hg (all p < 0.05 versus post-alcohol ablation). CONCLUSIONS: Myectomy can be successfully performed after failed alcohol ablation, but with a higher incidence of heart block than in cases where only surgery is performed. Otherwise, alcohol ablation does not appear to adversely affect surgical outcome.     

Comparison of surgical septal myectomy and alcohol septal ablation with cardiac magnetic resonance imaging in patients with hypertrophic obstructive cardiomyopathy.

OBJECTIVES: This study sought to describe the acute morphologic differences that result from septal myectomy and alcohol septal ablation using cardiac magnetic resonance (CMR) imaging. BACKGROUND: Surgical septal myectomy and alcohol septal ablation relieve left ventricular outflow tract obstruction in severely symptomatic patients with hypertrophic cardiomyopathy (HCM). METHODS: Cine and contrast-enhanced CMR images were obtained in HCM patients before and after septal myectomy (n = 24) and alcohol septal ablation (n = 24). Location of septal reduction, extent of myocardial necrosis, and conduction system abnormalities with each technique were compared. RESULTS: With septal myectomy, there was a discrete area of resected tissue consistently localized to anterior septum. In contrast, alcohol septal ablation resulted in a more variable effect. In most patients, alcohol septal ablation caused a transmural region of tissue necrosis, located more inferiorly in the basal septum than myectomy and usually extending into the right ventricular side of the septum at the midventricular level. However, there were 6 patients after alcohol septal ablation in whom there was sparing of the basal septum with residual gradients at follow-up. After the procedure, left bundle branch block developed in 46% of septal myectomy patients, and right bundle branch block was evident in 58% of alcohol septal ablation patients. CONCLUSIONS: Septal myectomy and alcohol septal ablation for severely symptomatic, drug-refractory patients with obstructive HCM have different morphologic effects and location sites on left ventricular septal myocardium. Septal myectomy provides consistent resection of the obstructing portion of the anterior basal septum, whereas the effect of ethanol septal ablation is more variable. These findings may have important implications for patient selection and management as well as long-term outcome.     

Symptomatic hypertrophic obstructive cardiomyopathy: the role of dual-chamber pacing

BACKGROUND AND PURPOSE: The management of symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM) has traditionally consisted of beta blockers and calcium channel blockers. Surgical treatment has been employed for operable patients who became refractory to medical therapy. However, associated complications, mortality rate, and recurrence of functional limitations have shifted the focus toward alternative therapy modalities. Recently, permanent dual-chamber (DDD) pacemaker has been introduced as an alternative treatment option. PATIENTS AND METHODS: This study comprises clinical, angiographic, echocardiographic, and electrophysiologic data obtained at a single center on 10 symptomatic patients with HOCM who received a DDD pacemaker after medical therapy failed to relieve symptoms. Presenting symptoms were exertional dyspnea and chest pain (60%), syncope (20%), and presyncope (20%). These symptoms were documented for 8.9+/-7.1 years before pacemaker implantation. All patients were in New York Heart Association functional class III or IV before pacemaker therapy. RESULTS: Placement of a permanent DDD pacemaker decreased the left ventricular outflow tract gradient from 83+/-44 mm Hg (range: 35-180 mm Hg) to 47.1+/-25.3 mm Hg (range: 10-75 mm Hg) in these patients. Within 1 to 30 months, follow-up found that the functional status of eight out of the 10 patients had improved to New York Heart Association class 0 or I. CONCLUSION: In selected patients with symptomatic HOCM who fail to respond to medical therapy, DDD pacemaker may offer a nonsurgical alternative treatment option. Large-scale multicenter, prospective, randomized trials are needed to establish the role of this modality in the treatment of hypertrophic obstructive cardiomyopathy.     

Exercise performance after septal myotomy and myectomy in patients with obstructive hypertrophic cardiomyopathy

The effect of left ventriculomyotomy and myectomy on exercise capacity and cardiac function in patients with obstructive hypertrophic cardiomyopathy has not previously been determined. In this study, 29 patients were evaluated during graded treadmill exercise before and after operation. Postoperatively, 27 of 29 patients reported symptomatic improvement and had greatly reduced left ventricular outflow gradient. Twenty-five of 28 patients (89 percent) attained higher exercise levels after operation, and this was accompanied by an increase in total body oxygen consumption from 16 to 21 ml/min per kg (P less than 0.005). A significant increase in cardiac index during maximal exercise also accompanied this improved exercise performance (5.0 to 5.7 liters/min per m2, P less than 0.05). The increase in maximal cardiac index was associated with greater desaturation of mixed venous blood (34 to 24 percent, P less than 0.02) in patients with preoperative angina. At a given level of mixed venous oxygen saturation (30 percent), overall mean cardiac index was higher postoperatively (4.6 to 5.2 liters/min per m2, P less than 0.05). These results suggest that, although several mechanisms probably contribute to symptomatic improvement after myotomy and myectomy, enhanced cardiac performance plays an important role in the majority of patients.     

Effects of dual-chamber pacing on regional myocardial deformation in patients with hypertrophic obstructive cardiomyopathy.

BACKGROUND: This study examined the effects of dual-chamber pacing (DDD) on regional myocardial deformation, as determined by echocardiographic strain and strain rate (SR) imaging, in patients with hypertrophic obstructive cardiomyopathy (HOCM). METHODS AND RESULTS: Fourteen patients (11 men, 3 women; mean age 55 +/-16 years) who had been on long-term DDD (mean period 7.4 +/- 2.1 years) underwent strain and SR imaging. Before and after DDD, the peak strain (%) and SR (s(-1)) during systole were assessed in 8 segments in 4 left ventricular (LV) walls. With DDD turned on, peak strain and SR were significantly increased in the basal anteroseptal (strain -10.2 +/- 6.8 to -1.0 +/- 6.4, p<0.005; SR -0.76 +/- 0.46 to 0.05 +/- 0.58, p<0.001) and septal segments (strain -11.2 +/- 8.9 to -2.2 +/- 7.7, p<0.005; SR -0.85 +/- 0.54 to -0.19 +/- 0.75, p<0.05), but not in the basal posterior (strain -15.0 +/- 13.0 to -13.4 +/- 9.2, p=NS; SR -1.37 +/- 0.57 to -1.93 +/- 0.65, p=NS) and lateral segments (strain -18.1 +/- 10.2 to -15.7 +/- 5.6, p=NS; SR -1.33 +/- 0.68 to -0.84 +/- 0.88, p=NS). These findings were associated with a modest, but significant, change in the LV pressure gradient (24 +/- 12 mmHg to 14 +/- 7 mmHg, p<0.001). CONCLUSIONS: In patients with HOCM, DDD appeared to produce myocardial lengthening in the basal septum during systole, which may have implications for the mechanism of reducing LV outflow obstruction during DDD.     

肥厚梗阻性心肌病双腔起搏与经皮室间隔化学消融治疗的远期疗效分析

目的 回顾性分析肥厚梗阻性心肌病患者行双腔起搏器植入(PM)或经皮室间隔化学消融(PTMSA)治疗,评价两种治疗方法的远期疗效.方法 48例患者,19例行PM治疗,29例行PTMSA治疗,并随访超声心动图结果.电话随访患者的临床症状.结果 PM组,平均年龄(51±13)岁,平均随访时间(3.9±2.3)年,起搏模式为DDD,AV延迟间期90～110 ms,治疗前后左心室流出道压力阶差分别是(103.8±40.6)mm Hg(1 mm Hg=0.133 kPa)和(45.1±36.2)mm Hg,P<0.05.PTMSA组,平均年龄(43±11)岁,随访时间(3.6±1.2)年,治疗前后左心室流出道压力阶差分别是(85.7±21.1)mm Hg和(24.6±12.2)mm Hg,P<0.05.PTMSA组左心室流出道压力阶差下降幅度大于PM治疗组[(71±12)%vs(58±29)%,P<0.05].PTMSA术后并发症为心律失常,发生率38%,主要为各种心律失常;PM术后主要为起搏器相关并发症发生率5.3%,主要为起搏器相关并发症.PTMSA组14例有晕厥史的患者中有1例术后活动时仍偶发晕厥,胸痛、胸闷症状缓解率75%.PM组10例有晕厥史的患者术后未再发,胸痛、胸闷症状缓解率93.8%.结论 双腔起搏器及经皮室间隔化学消融治疗肥厚梗阻性心肌病均可降低患者的左心窒流出道压力阶差,起搏治疗降低危心室流出道雎力阶差的幅度低于消融治疗.消融治疗的并发症高于起搏治疗.两种治疗方法均可改善患者临床症状.     

Impact of septal myectomy on diastolic function in patients with obstructive hypertrophic cardiomyopathy

BackgroundThe impact of septal myectomy on diastolic function in patients with obstructive hypertrophic cardiomyopathy is not well studied.MethodsA transcatheter hemodynamic study was performed before and 3 to 6 months after septal myectomy in 12 patients with obstructive hypertrophic cardiomyopathy (HCM).ResultsPostoperative hemodynamic studies were done 4.4±1.2 months after myectomy. The left ventricular outflow tract peak-to-peak gradient decreased from 83.2±43.3 mmHg preoperatively to 11.6±4.3 mmHg after myectomy (P<0.00). The left ventricular diastolic time constant (Tau) was 64.2±26.1 ms before surgery and 42.2±15.7 ms postoperatively (P=0.029). The average left atrial pressure (LAP) decreased from 20.2±7.0 to 12.1±4.5 mmHg after myectomy (P=0.008). Pulmonary artery hypertension was present in 6 patients preoperatively and remained in 2 patients after myectomy. Mean pulmonary artery pressure decreased from 29.3±16.2 to 20±6.7 mmHg after surgery (P=0.05), and the systolic pulmonary artery pressure decreased from 46±26.9 to 30.5±8.3 mmHg (P=0.048). Pulmonary vascular resistance decreased from 5.7±4.1 to 3.6±1.6 wood after surgery (P=0.032).ConclusionsSeptal myectomy improved left ventricular diastolic function and subsequently relieved the right ventricular congestion in patients with obstructive HCM.     

Evidence for anti-ischemic effect of dual-chamber pacing in patients with the obstructive form of hypertrophic cardiomyopathy

Dual-chamber pacing reportedly improves the quality of life by reducing the frequency of anginal episodes in selected patients with the obstructive form of hypertrophic cardiomyopathy (HCM), although the underlying mechanism or coronary effect is poorly understood. We report 3 patients with obstructive HCM, in whom the effects of atrial vs. dual-chamber tachypacing on systemic hemodynamics and myocardial lactate metabolism were studied. In all patients myocardial lactate production, objective evidence of myocardial ischemia, was demonstrated during atrial pacing, whereas no patient developed myocardial ischemia during dual-chamber pacing. By contrast, the responses of pressure gradient to pacing varied among the patients. These observations demonstrate for the first time that dual-chamber pacing exerted an anti-ischemic effect in obstructive HCM, which may contribute, at least partly, to the beneficial effects of chronic AV pacing on angina status and/or LV function.     

肥厚型梗阻性心肌病患者行左心室流出道疏通术的麻醉管理

目的:总结肥厚型梗阻性心肌病(HOCM)患者行左心室流出道疏通术的麻醉管理经验。方法:70例HOCM患者在全身麻醉体外循环下行左心室流出道疏通术,麻醉诱导和麻醉维持采用咪达唑仑、丙泊酚、异氟烷、芬太尼和哌库溴铵,术中持续监测ECG、HR、脉搏血氧饱和度(SPO2)、有创动脉血压(IBP)、中心静脉压(CVP)、心输出量(CO)、心脏排血指数(CI)、外周血管阻力(SVR)、肺血管阻力(PVR)及平均肺动脉压(MPAP)。术中部分患者使用艾司洛尔、去氧肾上腺素及地尔硫卓等维持血液动力学平稳。结果:术中血液动力学平稳,无严重心律失常发生,全组均顺利完成手术。结论:麻醉管理的关键在于①以适度的麻醉深度避免抑制心肌收缩力;②维持正常的心率和血压,酌情使用增强心肌收缩力的药物;③维持好前后负荷,避免使用血管扩张药;     

Long-term outcomes and risk factors for mortality of patients with hypertrophic obstructive cardiomyopathy undergoing septal myectomy

BackgroundWe aimed to evaluate the long-term surgical outcomes of patients with hypertrophic obstructive cardiomyopathy and explore the risk factors for mortality, especially those related to atrial fibrillation.MethodsWe retrospectively reviewed 150 consecutive patients with hypertrophic obstructive cardiomyopathy who underwent surgical treatment between March 2003 and December 2020.ResultsFifty (33.3%, age 53.7±16.1 years) patients underwent isolated septal myectomy (SM), 79 (52.7%, age 52.3±12.6 years) underwent SM with mitral valve intervention (SM + MVI), and 21 (14.0%, age 57.1±13.5 years) underwent SM with mitral valve replacement (SM + MVR). Overall peak left ventricular outflow tract pressure gradient at rest was significantly decreased from 91.9±43.2 to 13.3±13.0 mmHg (P<0.0001). Survival rates were 96.7%, 89.1%, and 81.5% at 30 days, 5 years, and 10 years, respectively. Patients in the SM + MVI group survived longer than those in SM + MVR or isolated SM groups (94.1% vs. 75.4% vs. 88.0%, respectively, at 5 years, P=0.05). Patients with preoperative atrial fibrillation had a worse 5-year survival rate than those without atrial fibrillation (73.4% vs. 92.8%, respectively, P<0.001). Preoperative atrial fibrillation was an independent risk factor for late mortality in multivariable analysis. Notably, those whose atrial fibrillation was successfully eradicated by surgical ablation had a better 5-year survival rate than other patients (87.7% vs. 28.6%, respectively, P<0.001).ConclusionsSurgical outcomes in hypertrophic obstructive cardiomyopathy are favorable in the long-term, except in patients with preoperative atrial fibrillation. Therefore, intraoperative ablation for preoperative atrial fibrillation in hypertrophic obstructive cardiomyopathy should be actively considered to improve patient outcomes.